2003 Nuevo Leon raids

The 2003 Nuevo Leon raids occurred on 14 March 2003 when the Mexican Army attempted to capture Gulf Cartel leaders Osiel and Antonio Cardenas Guillen. The army succeeded in capturing Osiel, but not Antonio, who was freed after a Los Zetas counterattack. The raids left scores of gunmen dead on both sides, with the Mexican soldiers (loyal to the Sinaloa Cartel) and the Sinaloa gunmen being forced to retreat after suffering heavy losses. The failure to conquer Nuevo Leon angered El Chapo, who was now dragged into a war with the Gulf.

History
On 14 March 2003, Sinaloa Cartel boss Joaquin Guzman Loera arranged for the military to capture rival Gulf Cartel boss Osiel Cardenas Guillen, who had made his opposition to Guzman known after he refused to show up at a meeting where Guzman's drug cartel federation was formed. Guzman employed several rogue soldiers and Beltran Leyva Cartel enforcer Edgar Valdez Villarreal to take part in the raids against Cardenas Guillen and his brother and second-in-command, Antonio Cardenas Guillen. Osiel Cardenas Guillen was captured after a brief shootout at his ranch in the Tolerancia Zone in Nuevo Laredo, while the military trucks shot their way through Los Zetas guards as they hunted down Antonio in Los Arcos township, Nuevo Leon. The Sinaloa mercenaries took over much of the city, engaging in drive-by shootings and killing the guards. Valdez also hung a flag that warned Los Zetas that they had one day to evacuate Nuevo Leon. Just then, the Gulf Cartel's Los Zetas mercenaries launched a massive counterattack, catching the Sinaloa Cartel members off guard. Antonio Cardenas Guillen was briefly captured, but he was later able to escape after Los Zetas brought up an armored vehicle and reinforcements to fight off the few surviving Sinaloa mercenaries. El Chapo was forced to allow for his men to retreat, as most of them had been killed.

The raids led to a war between El Chapo's federation and the Gulf Cartel, and it also led to Los Zetas leader Heriberto Lazcano Lazcano becoming a well-known murderer. Antonio Cardenas Guillen took over the Gulf Cartel as boss after his brother's capture, and Lazcano was quick to tell Cardenas that, in times of war, the military was given full control of the situation, and Cardenas would be forced to allow for Los Zetas to become dangerously independent and violent.